Peroxide bleaching agents for use in laundering have been known for many years. Such agents are effective in removing stains, such as tea, fruit, and wine stains, from clothing at or near boiling temperatures. The efficacy of peroxide bleaching agents drop off sharply, however, at temperatures below about 60.degree. C. To lower the temperature at which peroxide bleaching agents are effective, metal complexes capable of activation of catalysis are combined with the bleaching agents.
For example, environmentally acceptable manganese ions and complexes are known for this purpose. U.S. Pat. No. 4,728,455 discusses the use of a Mn(III)-gluconate complex as a peroxide bleach catalyst with high hydrolytic and oxidative stability. However, relatively high ratios of ligand (gluconate) to Mn are needed to obtain the desired catalytic system. Moreover, the performance of this Mn-based catalyst is inadequate when used for bleaching in the low-temperature region of about 20-40.degree. C. Furthermore, it is restricted in its efficacy at removing a wide range of stains. EP-A-458,379 discusses a triazacyclononane-based manganese complex that displays a high catalytic oxidation activity at low temperatures, which is particularly suitable for bleaching purposes. It is believed that this improvement in bleaching activity is due to the fact that these compounds are stable under washing conditions, e.g., high alkalinity and oxidizing environment (as a result of the presence of hydrogen peroxide or peroxy acids).
In addition to the above-mentioned stain removal, dye transfer is a well-known problem in the art and has been addressed in various ways. For instance, an improved dye transfer inhibition has been obtained by using Fe-porphyrin and Fe-phtalocyanine complexes. See, for example, EP-A-537,381, EPA-553,607, EP-A-538,228.
It is well known that the stability of Fe-coordination complexes in alkaline aqueous media in the presence of peroxide compounds is very poor. This poor stability of Fe-coordination species has resulted in the necessity of very low concentrations of peroxide and, additionally, the use of polymers. See, for example, EP-A-538,228. These measures, however, only reduce the negative effects of this poor stability to some extent and do not provide a complete solution for the problem.
Improvement in activity and stability of iron compounds has been recently disclosed in WO 95 34628. By employing pentadentate ligands, the stability of the iron species has been significantly enhanced. This resulted in a catalytic system that is particularly useful for stain removal and dye bleaching in solution. Still the synthesis of the complex, and in particular of the ligand employed, leaves room for improvement. Furthermore, the remarkable anti-dye transfer properties have been obtained by using peroxyacids rather than hydrogen peroxide, which is desirable at least because of the expense associated with peroxyacids. Thus, there is a need for additional relatively stable complexes that can activate peroxy compounds in detergent compositions.
There is also a need for complexes that can stereospecifically hydroxylate hydrocarbons. The stereospecific functionalization of aliphatic C--H bonds is important in chemistry and biochemistry for drug synthesis, perfume synthesis, etc. Such transformations have been carried out by organic peroxides in a stoichiometric fashion using oxidants such as (CF.sub.3).sub.2 -dioxirane, p-NO.sub.2 -perbenzoic acid, and perfluorodialkyloxaziridines, on substrates such as 1,2-dimethylcyclohexane and decalin. However, the prospect of using metal complexes in combination with readily available oxidants (e.g., O.sub.2, H.sub.2 O.sub.2, or ClO.sup.-) to carry out such reactions catalytically has aroused considerable interest in such endeavors. The latter has been inspired by the availability of metalloenzymes such as cytochrome P450, methane monooxygenase, and dopamine .beta.-hydroxylase, which respectively utilize a heme iron, a nonheme iron, and a copper center to catalyze stereospecific hydroxylation of an alipahtic C--H bond in an enzyme active site. Iron porphyrin complexes have been successfully used as catalysts for stereospecific hydroxylation of hydrocarbons; however, the susceptibility of the porphyrin to oxidative self-degradation and the usual requirement for an expensive oxidant like PhIO have limited the utility of this approach.
There is also a need for complexes that can stereospecifically epoxidize hydrocarbons. Iron porphyrin and iron cyclam complexes have been used as catalysts for stereospecific epoxidation of C.dbd.C bonds; however, the catalysts were shown to be susceptible to oxidative self-destruction within a short period of time.